This invention relates to magnetoresistive heads, particularly to magnetoresistive heads for reading data from an adjacent magnetic media.
Magnetoresistive (MR) elements are widely used in magnetic transducing heads for reading data from a magnetic disk. MR elements are characterized in that the resistance of the element changes with variations in the magnetic field due to recorded data on the adjacent magnetic disk. Resistance changes in the MR element are sensed by passing a current through the element and measuring the voltage change across it, or by placing a voltage across the element and measuring the current change through it. In either case, the varying signal represents the data on the disk and the MR head provides an accurate transducer for reading high density digital information from the adjacent magnetic media. Typically, the MR element is located on the magnetic head between two thick soft magnetic films, such as Sendust or permalloy, which act as flux shields for the MR head. Typically, these shields are isolated from the MR element by electrically insulating material, such as aluminum oxide (Al.sub.2 O.sub.3).
One problem associated with MR heads is that considerable heat is often generated by current passing through the MR element. Although the current is typically small (of the order of milliamperes), the size of the MR element film is likewise small, causing a substantial concentration of the heat in the MR element. While the magnetic film shields could provide a good heat sink for dissipating excess heat generated by the MR head, the presence of the electrically insulating layer between the magnetic films and the MR element thermally insulates the MR element from the magnetic material.
There is, accordingly, a need for at least one of the half-gaps adjacent the MR element be of a material that exhibits high thermal conductivity and low electrical conductivity.